Chambers aims at the target with both barrels

World Championships: Dwain's horizons now twice as wide as the 200m presents an even greater opportunity

Dwain Chambers is twice the runner he used to be. It took him 20.31sec at Crystal Palace last Sunday night to become more than just a 100m man. All of a sudden, in the wake of his stunning win from the outside lane in the Norwich Union British Grand Prix meeting, the Belgrave speed merchant is also a 200m runner to be reckoned with on the global stage. He will be going to Edmonton not as a singular golden shot but as a contender for two world championship titles.

The emergence of Chambers as a dual challenger could not have come at a better time for Britain. After Katharine Merry's withdrawal from the 400m on Thursday afternoon, Jonathan Edwards will be the only British athlete heading to Canada as a top-ranked favourite. Chambers stands ninth in the 200m world rankings this year, but four of the runners placed ahead of the young Londoner will not be contesting the event in Edmonton. Neither will Michael Johnson, the world record holder. And Maurice Greene, the reigning 200m champion, is likely to restrict himself to the 100m, for fear of aggravating tendonitis in his left knee with some high-risk bend-running.

"My focus is still on the 100m," Chambers said as he prepared to depart for Canada, "but the opportunities are more apparent in the 200m. Without Michael and without Maurice, the 200m is pretty open. I've only had three races at the distance this summer and I've run 20.31, so obviously I've got a lot more in store. Ideally, I'd like a medal from both events. I'll just go out there and give it my best shot." The double shot might never have materialised – and not just because the whole season was in serious doubt for Chambers when he lay in a hospital bed for two days at the beginning of April after dislocating his shoulder in a motorbike crash. By the end of May he was lying flat on his back on the Loughborough University track, exhausted by the vain effort of trying to catch Marlon Devonish in the 200m invitation race at the Aqua Pura International meeting. His time, 20.90sec, was hardly encouraging.

"I was going to call it a day then," Chambers reflected. Fortunately, however, he was persuaded to persist with the 200m by the two sprint gurus in his professional running life: his coach Mike McFarlane, who famously dead-heated with Allan Wells in the 1982 Commonwealth Games 200m final, and his manager, John Regis, holder of the British 200m record.

Third place in the AAA championships a fortnight ago – clocking 20.65sec behind Devonish and Christian Malcolm – was a personal best for Chambers and a step in the World Championship direction. First place at Crystal Palace was a quantum leap. Regis leapt out of his seat in the BBC television commentary box as Chambers blitzed round the bend and put clear daylight between himself and established 200m men like Malcolm (the reigning European indoor champion), Kevin Little (a former world indoor champion), Devonish (the AAA champion) and Frankie Fredericks (a former world champion). As he had done at Loughborough, Chambers collapsed on to the track once again – this time not in exhaustion but in sheer amazement.

For all his reluctance to run at the double, the chart of Chambers' progress as a 200m runner is following a steeply upward path encouragingly similar to that of Darren Campbell last year. In fact, Chambers has now run the distance 0.16sec faster than his Belgrave club-mate had on the eve of the Sydney Olympics. Campbell, of course, returned with the silver medal. Injury has hamstrung his World Championship ambitions but the man who beat him in Sydney, Konstantinos Kenteris, is in flying form. The Greek air force officer clocked 20.10sec in Athens last month. Ramon Clay of the USA leads the world rankings with 20.05sec, though on the evidence provided at Crystal Palace a week ago Chambers could well become the second Briton to finish among the world championship 200m medals. Regis took bronze in Rome in 1987 and silver in Stuttgart in 1993.

At 23, Chambers is already one of two British sprinters who have won world championship medals at 100m. In Seville two years ago he was third behind Greene and the Canadian Bruny Surin. With the best years of his career still surely ahead of him, he could be the first Briton to finish in the top three in two 100m finals. Linford Christie was elevated from fourth place to the bronze-medal position in the revised 1987 result when Ben Johnson was disqualified five years after the event. The prospect of Chambers emulating Christie's golden run in Stuttgart eight years ago, however, is distinctly remote.

After running 10.01sec in Seville in early June Chambers talked the talk about "gunning for Greene this year – big time". He has not, however, managed to sprint the sprint against the world's fastest man. He was a well beaten third behind Greene in Lausanne on 4 July and he was a clear stride adrift in the 100m race at Crystal Palace a week ago.

Chambers finished second in 10.11sec. Greene was a comfortable winner in 9.98sec – the 38th sub-10-seconds clocking of the American's career, his seventh in eight races this season. Chambers has dipped under the barrier just twice, running 9.99sec in Nuremburg two years ago and 9.97sec in the world championship final in Seville the same summer.

"Obviously Maurice is the driving force at the moment," Chambers acknowledged. "But anybody is beatable. When the pressure's on in a championship anything can happen." As the record books show, however, when the pressure has been on at the last three global championships – at the World Championships in 1997 and 1999 and at last year's Olympics – it is Greene who has emerged with the 100m gold. Chambers, it seems, will have to run twice as far if he is to find a Midas touch in Edmonton.